Re: GPLv3 and the GMGPL

[Waldek Hebisch <hebisch@math.uni.wroc.pl>]

Nick Roberts <nick.roberts@acm.org> wrote:
> The Free Software Foundation (FSF) - http://www.fsf.org - is currently 
> canvassing opinion before finalising a new version of the General Public 
> License (GPLv3). A draft is available for comment:
> 
>     http://gplv3.fsf.org
> 
> Ada software published under the current version of the GPL (GPLv2) 
> tends to carry a special exception, which (since I suppose it originated 
> with GNAT) is generally called the GNAT-Modified GPL (or GMGPL):
> 
> "As a special exception, if other files instantiate generics from this 
>          Unit, or you link this unit with other files to produce an 
> executable, this unit does not by itself cause the resulting executable 
> to be covered by the GNU General Public License.  This exception does 
> not however invalidate any other reasons why the executable file might 
> be covered by the GNU Public License."
> 
> The new GPL (in its current draft) defines what it calls the "Complete 
> Corresponding Source Code" in a way suggests (to me) that the GNAT 
> modification might no longer be required, in many cases. This is because 
> the new definition provides an exception:
> 
> "As a special exception, the Complete Corresponding Source Code need not 
> include a particular subunit if (a) the identical subunit is normally 
> included as an adjunct in the distribution of either a major essential 
> component (kernel, window system, and so on) of the operating system on 
> which the executable runs or a compiler used to produce the executable 
> or an object code interpreter used to run it, and (b) the subunit (aside 
> from possible incidental extensions) serves only to enable use of the 
> work with that system component or compiler or interpreter, or to 
> implement a widely used or standard interface, the implemention of which 
> requires no patent license not already generally available for software 
> under this License."
> 
> I suspect that most of the actual difficulties the GNAT modification was 
> added to resolve are now solved by the new wording of the GPLv3.
> 

GPL Version 2 section 3 contains the following:

:     However, as a special exception, the source code distributed need
:     not include anything that is normally distributed (in either
:     source or binary form) with the major components (compiler,
:     kernel, and so on) of the operating system on which the executable
:     runs, unless that component itself accompanies the executable.

Both the the exception in GPL 2 and the quoted text form GPL 3 allow
creation of GPL-ed programs which hook into closed-source infrastructure.
GPL 2 is probably more explicit, but IMHO novelty of GPL 3 is that
GPL 3 allows GPL-ed binary linked with closed-source JVM, while GPL 2
would exclude JVM (since usually it is not a part of the OS).
GMGPL allows closed-source program which hook into GMGPL-ed infrastructure
-- that is quite different.

Disclaimer: I did not look at GPL 3, just comment the enclosed quote.

-- 
                              Waldek Hebisch
hebisch@math.uni.wroc.pl